Do you really want to trap the error, or do you want to fix the problem? The error is currently trapped and logged by the default FoxWeb error handler. In order to identify and fix the problem, you will need to use one of the techniques described in the Debugging FoxWeb Scripts topic of the FoxWeb documentation. One thing that would help is to switch to using the full version of FoxWeb instead of the run-time DLL. This will allow you to identify the line number of the problem code (note that with FoxWeb 3 the line number would be visible even when using the VFP run-time DLL).

The www_run procedure is part of the FoxWeb foundation code. This code calls fw_start and then passes control to your script.